Despite their highly exotic appearance, African cichlids are actually one of the hardiest families of freshwater fish.
Sexual reproduction in all animals depends on effective communication between signalers and receivers. Many fish species, especially the African cichlids, are well known for their bright coloration and the importance of visual signaling during courtship and mate choice, but little is known about what role acoustic communication plays during mating and how it contributes to sexual selection in this phenotypically diverse group of vertebrates. Here we examined acoustic communication during reproduction in the social cichlid fish, Astatotilapia burtoni. We characterized the sounds and associated behaviors produced by dominant males during courtship, tested for differences in hearing ability associated with female reproductive state and male social status, and then tested the hypothesis that female mate preference is influenced by male sound production. We show that dominant males produce intentional courtship sounds in close proximity to females, and that sounds are spectrally similar to their hearing abilities. Females were 2–5-fold more sensitive to low frequency sounds in the spectral range of male courtship sounds when they were sexually-receptive compared to during the mouthbrooding parental phase. Hearing thresholds were also negatively correlated with circulating sex-steroid levels in females but positively correlated in males, suggesting a potential role for steroids in reproductive-state auditory plasticity. Behavioral experiments showed that receptive females preferred to affiliate with males that were associated with playback of courtship sounds compared to noise controls, indicating that acoustic information is likely important for female mate choice. These data show for the first time in a Tanganyikan cichlid that acoustic communication is important during reproduction as part of a multimodal signaling repertoire, and that perception of auditory information changes depending on the animal's internal physiological state. Our results highlight the importance of examining non-visual sensory modalities as potential substrates for sexual selection contributing to the incredible phenotypic diversity of African cichlid fishes.
The African cichlid fish, Astatotilapia burtoni (TaxonomicAuthority) (formerly Haplochromis burtoni) has become an importantmodel system to study the mechanisms underlying socially mediated behavioralchange. In this species, 20–30% of males are dominant (D), slow growing,brightly coloured and actively defend territories for mating. The remainingsubordinate (S) males mimic females by schooling and displaying crypticcoloration, while experiencing faster growth(;).Subordinate males show little aggression and territoriality and, importantly,have regressed gonads and are thus not reproductive(;;). Thesebehavioral and physiological characteristics are plastic and influenced by theimmediate social environment, such that an individual male switches betweenthe D and S phenotypes several times during its life depending upon itsrelative ability to obtain and maintain access to a territory throughencounters with other males (). Environmental conditions, availability of territorialshelters, relative body size and physiological condition influence theprobability of acquiring and maintaining a territory. The phenotypic switchoccurs over a timescale of minutes to days to weeks in both the field and thelaboratory (; ; ).
Cichlids: Fish Guides for African, South American, Dwarf Cichlids
Freshwater Aquarium Fish Species Profile: African Cichlid